Use of Stable Isotopes in Benthic Organic Material as a Baseline for Estimating Fish Trophic Positions in Lakes
Ontology highlight
ABSTRACT: Estimating the trophic position of predators in food webs using stable isotopes requires establishing a 'baseline'; typically served by bivalves or snails. However, the frequent absence of such organisms in lakes leaves researchers in a difficult situation. Here we test the hypothesis that trophic position (TP) of largemouth bass (LB) in lakes can be estimated from ?15N of benthic organic material (BOM) in littoral surficial sediment. ?15NLB as a function of ?15NBOM was significant across 51 lakes with an R2 of 0.84, supporting our hypothesis. In a subset of six lakes, the mean TPLB did not differ significantly when calculated using baselines of ?15N in BOM, mussels (UN), gastropods (SN), or from a stable isotope mixing model. In a subset of 26 lakes, mean TPLB calculated from ?15NBOM and ?15NUN baselines were not significantly different, but TPLB calculated using ?15NBOM was not significantly correlated with TPLB calculated using ?15NUN. Although ?15NBOM should not be used interchangeably with ?15NUN as a baseline for estimating TPLB, ?15NBOM can be useful as a separate baseline where estimates of fish TP are needed in all study lakes given that mussels are frequently absent and BOM is always available for collection.
SUBMITTER: Lake J
PROVIDER: S-EPMC7751643 | biostudies-literature | 2019 Jul
REPOSITORIES: biostudies-literature
ACCESS DATA